[Bug target/114402] rs6000: ICE when long double is ieee128 format by default but without vsx

[linkw at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114402

--- Comment #1 from Kewen Lin <linkw at gcc dot gnu.org> ---
Currently the only pattern to match IEEE128 comparison is:

;; IEEE 128-bit comparisons
(define_insn "*cmp<mode>_hw"
  [(set (match_operand:CCFP 0 "cc_reg_operand" "=y")
        (compare:CCFP (match_operand:IEEE128 1 "altivec_register_operand" "v")
                      (match_operand:IEEE128 2 "altivec_register_operand"
"v")))]
  "TARGET_FLOAT128_HW && FLOAT128_IEEE_P (<MODE>mode)"
   "xscmpuqp %0,%1,%2"
  [(set_attr "type" "veccmp")
   (set_attr "size" "128")])

It requires TARGET_FLOAT128_HW, so nothing can be used for matching.

The below patch can fix this ICE, it makes no-vsx IEEE128 also go with libfunc
call like !TARGET_FLOAT128_HW && FLOAT128_VECTOR_P (mode).

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 5d975dab921..237d138faec 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -15329,7 +15329,7 @@ rs6000_generate_compare (rtx cmp, machine_mode mode)
   rtx op0 = XEXP (cmp, 0);
   rtx op1 = XEXP (cmp, 1);

-  if (!TARGET_FLOAT128_HW && FLOAT128_VECTOR_P (mode))
+  if (!TARGET_FLOAT128_HW && FLOAT128_IEEE_P (mode))
     comp_mode = CCmode;
   else if (FLOAT_MODE_P (mode))
     comp_mode = CCFPmode;
@@ -15361,7 +15361,7 @@ rs6000_generate_compare (rtx cmp, machine_mode mode)

   /* IEEE 128-bit support in VSX registers when we do not have hardware
      support.  */
-  if (!TARGET_FLOAT128_HW && FLOAT128_VECTOR_P (mode))
+  if (!TARGET_FLOAT128_HW && FLOAT128_IEEE_P (mode))
     {
       rtx libfunc = NULL_RTX;
       bool check_nan = false;